Si nanohole array (Si NHA)-based type-I heterojunction for filterless self-powered ultraviolet photodetection

We report the fabrication of an Si nanohole array (NHA)/SnO type-I heterostructure by depositing a p-SnO film onto an n-Si NHA substrate through RF magnetron sputtering using a high-purity Sn target. For the Si NHA with a period of 300 nm, stronger UV light trapping is expected. Moreover, due to the large valence band offset, the transportation of photogenerated holes in the Si side is impeded. This suppresses the contribution of visible and near-infrared absorption in Si to the photoresponse, resulting in a response dominated by the wide-bandgap SnO film. The device functions well as a self-powered, filterless UV photodetector, showing a responsivity of 0.28 A W⁻¹, a specific detectivity of 1.10 × 10¹³ Jones, and a fast response speed (240/190 μs for rise/fall) under 265 nm illumination. The device also exhibits promising potential for anti-interference UV communication.